Dmitrij Ivanovič Mendeleev (1834–1907): Zum 100. Todestag

The 100th anniversary of death of Mendeleev is occasion for us to appreciate live and work of this great scientist whose name is inseparable from the periodical system of elements and who accomplished pathbreaking benefits not only in the chemical field.     

Indigo – 100 Jahre industrielle Synthese

Up until 100 years ago, indigo was derived mainly from the indigo plant, cultivated in huge plantations in the Indian subcontinent. Developing an industrial synthesis for the king of dyes was a challenge for both scientists and entrepreneurs. BASF, as well as Hoechst, played a decisive role in this venture. It took 17 years of development and enormous financial investment – around 18 million gold marks, an amount exceeding the company's share capital of the day – before the first Indigo Pure BASF was manufactured and brought on to the market in July 1897. Of the various alternative synthesis routes that became available initially, only the Heumann-Pfleger process proved successful in the long term, and it is still the standard method of industrial indigo manufacture. In his process, phenylglycine, produced from aniline, formaldehyde and hydrogen cyanide, is fused with sodium amide under anhydrous, alkaline conditions.     

From Planck to Bohr

The quantum theory, which is nowadays a fundamental basis of chemistry that is regarded as self-evident, initially presented immense difficulties to human thought. An insight into many particulars of its fascinating evolution is provided by the correspondence of those involved in the development of the theory between 1899 and 1913, which has now been thoroughly sifted for the first time by the author.     

Adiponitrile at 100 K

Adiponitrile, C₆H₈N₂, is a key intermediate in the synthesis of the polyamide Nylon 66 and is produced industrially on a large scale. We have determined the crystal and molecular structure of adiponitrile by single‐crystal X‐ray analysis at 100 K, a suitable crystal (m.p. 275 K) having been grown from the melt at low temperature. The compound crystallizes in the monoclinic space group P 2₁/c with Z = 2. In the crystal structure, the molecule adopts an exact C_i‐symmetric gauche –anti –gauche conformation of the C—C—C—C skeleton about an inversion centre. The molecules are densely packed, with short intermolecular contacts between the α‐H and nitrile N atoms.     

Niels Bohr (1885–1962): On the Wing of a Butterfly,Johann J. Balmer (1825–1898)

By the year 1913, a number of revolutionary events had begun to transform the landscape of physics. In 1900, Max Planck (1858–1947) had proposed that energy radiated in quanta or packets. The announcement of the photoelectric effect in 1905 by an unassuming Swiss patent worker by the name of Albert Einstein (1879–1955) clearly implicated that light energy, or the photon, later coined by Gilbert N. Lewis (1875–1946) in 1926, was also quantized and showed unprecedented particle‐like properties. More startling was the discovery by Ernest Rutherford (1871–1937) who demonstrated that the atom consisted of a hard positive center surrounded by electrons. Niels Bohr (1885–1962), then a young postgraduate, was deeply involved in understanding the structure of the atom. He needed physical or experimental evidence to substantiate his intuitive ideas. Ironically, that evidence had already been published in the year of his birth by Johann J. Balmer (1825–1898), a Swiss mathematics teacher at a secondary school for girls.